document.write( "Question 80375This question is from textbook Algebra for college students
\n" ); document.write( ": Find the Inverse of the function f(x)= 2/3x -3/5.
\n" ); document.write( "I know the answer is f-1(x)= -6-x
\n" ); document.write( " -----
\n" ); document.write( " 3\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "I only need to know the solution on how it was figured out.\r
\n" ); document.write( "\n" ); document.write( "Thank you.
\n" ); document.write( "

Algebra.Com's Answer #57678 by bucky(2189)\"\" \"About 
You can put this solution on YOUR website!
Given:
\n" ); document.write( ".
\n" ); document.write( "\"f%28x%29+=+%282%2F3%29x+-+%283%2F5%29\"
\n" ); document.write( ".
\n" ); document.write( "Note that I presume you meant \"%282%2F3%29%2Ax\" and not \"2%2F3x\" which is what you wrote
\n" ); document.write( "if the rules of algebraic convention are followed.
\n" ); document.write( ".
\n" ); document.write( "There are four steps to finding an inverse of the function. These steps are:
\n" ); document.write( ".
\n" ); document.write( "1. Replace f(x) with y
\n" ); document.write( "2. Then replace y by x and also change x to y
\n" ); document.write( "3. Solve for y
\n" ); document.write( "4. Finally replace y by \"f%5E-1%28x%29\"
\n" ); document.write( ".
\n" ); document.write( "Let's do it by following these 4 steps. Start with the given:
\n" ); document.write( ".
\n" ); document.write( "\"f%28x%29+=+%282%2F3%29x+-+%283%2F5%29\"
\n" ); document.write( ".
\n" ); document.write( "Replace f(x) by y to get:
\n" ); document.write( ".
\n" ); document.write( "\"y+=+%282%2F3%29x+-+%283%2F5%29\"
\n" ); document.write( ".
\n" ); document.write( "Step 1 is done. Next do step 2 by changing y to x and also changing x to y. When you
\n" ); document.write( "do that the equation from step 1 becomes:
\n" ); document.write( ".
\n" ); document.write( "\"x+=+%282%2F3%29y+-+%283%2F5%29\"
\n" ); document.write( ".
\n" ); document.write( "Step 2 is now done. On to step 3 which tells you to solve for this equation for y.
\n" ); document.write( "You can isolate the term that contains y. Do that by adding \"3%2F5%29\" to both sides of
\n" ); document.write( "the equation to get:
\n" ); document.write( ".
\n" ); document.write( "\"x+%2B+%283%2F5%29+=+%282%2F3%29y+-%283%2F5%29+%2B+%283%2F5%29\"
\n" ); document.write( ".
\n" ); document.write( "Notice that the terms \"-3%2F5\" and \"3%2F5\" cancel each other on the right side so
\n" ); document.write( "the equation is reduced to:
\n" ); document.write( ".
\n" ); document.write( "\"x+%2B+%283%2F5%29+=+%282%2F3%29y\"
\n" ); document.write( ".
\n" ); document.write( "You can get rid of the denominator 5 on the right side by multiplying all the terms on
\n" ); document.write( "both sides of this equation by 5. Multiplying everything by 5 results in:
\n" ); document.write( ".
\n" ); document.write( "\"5x+%2B+3+=+%2810%2F3%29%2Ay+\"
\n" ); document.write( ".
\n" ); document.write( "Now get rid of the denominator of 3 on the right side by multiplying everything on both
\n" ); document.write( "sides by 3 to get:
\n" ); document.write( ".
\n" ); document.write( "\"15x+%2B+9+=+10y\"
\n" ); document.write( ".
\n" ); document.write( "Now solve for y by dividing both sides by 10 and the result is:
\n" ); document.write( ".
\n" ); document.write( "\"%2815x+%2B+9%29%2F10+=+y\"
\n" ); document.write( ".
\n" ); document.write( "Step 3 is done. Now replace y with \"f%5E-1%28x%29\" and the answer becomes:
\n" ); document.write( ".
\n" ); document.write( "\"f%5E-1%28x%29=+%2815x+%2B+9%29%2F10\"
\n" ); document.write( ".
\n" ); document.write( "Presuming that I interpreted your problem correctly, this is the answer you were asked to
\n" ); document.write( "find. I'm not sure where you got the answer that you did. Even if I interpreted it incorrectly,
\n" ); document.write( "the four step process is correct, and you can use this same method to solve any problem with
\n" ); document.write( "inverting a function.
\n" ); document.write( ".
\n" ); document.write( "
\n" ); document.write( "
\n" );